VOA科学技术2023--Scientists: South African Fossils Tell of the Struggle to Survive

Scientists: South African Fossils Tell of the Struggle to Survive

A recent study says fossil remains¹ of a top meat-eating animal living 250 million years ago, which had only been found in the world's northern half, also lived in South Africa.

The scientists all have links to South Africa. They reported on fossils of a large ancestor to today's mammals called Inostrancevia. The creature had only been known from fossils found in Russia near the Artic Sea until the new fossils were discovered at a farm in central South Africa.

The fossils suggest that Inostrancevia left its native area and moved about 12,000 kilometers over a period of hundreds or thousands of years. During that period, most of the world's big landmasses were connected in what scientists call Pangea.

Inostrancevia filled the ecological² place of a top meat-eating animal in South Africa that had been missing after four other species had died out.

"However, it did not survive there long," said Christian³ Kammerer. He is a scientist with the North Carolina Museum of Natural Sciences. Kammerer studies fossils and was the lead writer of the research published in Current Biology.

"They have no living descendants, but they are a member of the larger group called synapsids, which includes mammals as living representatives," Kammerer added.

Kammerer noted⁴ that Inostrancevia and all of its closest relatives disappeared in the mass extinction⁵ called "the Great Dying." The event took place at the end of what Earth scientists, or geologists⁶, call the Permian Period.

Scientists believe that life on Earth was under pressure about 250 million years ago. Some scientists say volcanic⁷ activity in today's Russian area called Siberia warmed Earth temperatures. It caused up to 90 percent of species to die out.

Inostrancevia is part of a group of animals called protomammals that combined reptile-like and mammal-like features. It was three to four meters long and had a large, long head with a set of huge teeth it used to kill and eat other animals. If the animals were small enough, Inostrancevia swallowed them whole.

Inostrancevia was structured differently from both reptiles⁸ and mammals but was usual for protomammals. It carried itself in a way that was neither flat to the ground like reptiles nor standing⁹ tall like mammals. It also lacked facial muscles found in mammals and did not produce milk.

"Whether these animals were furry¹⁰ or not remains an open question," Kammerer said.

The mass extinction happened over about one million years. It led to the rise of dinosaurs¹¹ during the following Triassic Period.

The scientists noted that top meat-eating animals are especially affected¹² by extinction because they require the most food and space.

The researchers said they see similarities between the Permian mass extinction and today's climate change problem.

Pia Viglietti is with the Field Museum in Chicago. She helped write the study. She said unlike the animals that came before us during the Permian Period, "we actually have the ability to do something to prevent this kind of ecosystem¹³ crisis from happening again."

Words in This Story

fossil –n. the mineralized remains of an animal or plant that lived a very long time ago

species – n. a group of animals or plants that are similar and can produce young animals or plants

extinction – n. the state or situation that results when something (such as a plant or animal species) has died out completely

mammal – n. a class of animal that feeds milk to its young and that usually has hair and special ear bones

descendant – n. a plant or animal that is related to a particular plant or animal that lived long ago

feature – n. an important part, quality, or ability

fur – n. the hairy coat of an animal especially when it is soft and thick

ecosystem – n. everything that exists in a particular environment

1 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

2 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

3 Christian   

adj.基督教徒的；n.基督教徒

参考例句：

• They always addressed each other by their Christian name.他们总是以教名互相称呼。
• His mother is a sincere Christian.他母亲是个虔诚的基督教徒。

4 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

5 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

6 geologists   

地质学家，地质学者( geologist的名词复数 )

参考例句：

• Geologists uncovered the hidden riches. 地质学家发现了地下的宝藏。
• Geologists study the structure of the rocks. 地质学家研究岩石结构。

7 volcanic   

adj.火山的；象火山的；由火山引起的

参考例句：

• There have been several volcanic eruptions this year.今年火山爆发了好几次。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

8 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

9 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

10 furry   

adj.毛皮的；似毛皮的；毛皮制的

参考例句：

• This furry material will make a warm coat for the winter.这件毛皮料在冬天会是一件保暖的大衣。
• Mugsy is a big furry brown dog,who wiggles when she is happy.马格斯是一只棕色大长毛狗，当她高兴得时候她会摇尾巴。

11 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

12 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

13 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。